DEVELOPMENT OF ACOUSTIC MODELS FOR HIGH FREQUENCY RESONATORS FOR TURBOCHARGED IC-ENGINES

• Main Author: Wang, Zheng
• Format: Others
• Language: English
• Published: KTH, MWL Marcus Wallenberg Laboratoriet 2012
• Subjects: Noise; turbo compressor; silencer; resonator
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-91335

Automotive turbo compressors generate high frequency noise in the air intake system. This sound generation is of importance for the perceived sound quality of luxury cars and may need to be controlled by the use of silencers. The silencers usually contain resonators with slits, perforates and cavities. The purpose of the work reported is to develop acoustic models for these resonators where relevant effects such as the effect of realistic mean flow on losses and possibly 3D effects are considered. An experimental campaign has been undertaken where the two-port matrices and transmission loss of four sample resonators has been measured without flow and for two different mean flow speeds (M=0.05 & M=0.1) using two source location technique. Models for the four resonators have been developed using a 1D linear acoustic code (SIDLAB) and a FEM code (COMSOL Multi-physics). Different models, from the literature, for including the effect of mean flow on the acoustic losses at slits and perforates have been discussed. Correct modeling of acoustic losses for resonators with complicated geometry is important for the simulation and development of new and improved silencers, and the present work contributes to this understanding. The measured acoustic properties compared well with the simulated model for almost all the cases.